Prevention of fuel knock



. tion.

what unsatisfactory under certain conditions and it is the object of thepresent invention to provide a composition of mat-- Patented Feb. 2,1926.

UNITED STATES PATENT OFFICE.

THOMAS MIDGLEY, JR., OF DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TOGENERAL MOTORS CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OFDELAWARE.

PREVENTION or FUEL KNOCK.

No Drawing. Continuation of application Serial No. 419,763, filedOctober 26, 1920. This application filed September 18, 1923. Serial No.663,505.

To all whom it may concern:

Be, it known that I, THOMAs Minster, Jr., a citizen of the United Statesof America, residing at Dayton, county of Montgomery, and State of Ohio,have invented certain new and useful Improvements in the Prevention ofFuel Knock, of which the following is a full, clear, and exactdescription.

The present invention relates to the prevention of the so-called fuelknock in internal-combustion engines.

In its preferred form, it relates more specifically to a composition ofmatter. for injection or addition to the fuel mixture of aninternal-combustion engine before the combustion of the same.

This application is a continuation of my application Serial No. 419,763, filed October 26, 1920. 'i

In application, Serial N01 553,040, filed April 15, 1922, there isdescribed a'method and apparatus for preventing knock ininernal-combustion engines, wherein aniline and other anti-knockmaterials are injected into the fuel-air mixture prior to its"combustion.

In application Serial No. 553,040, filed April 15, 1922, there isdescribed the use of these materials without specific prepara- Thesematerials however, are someter rcntaining anti-knock material which willhave satisfactory physical properties under all ordinary operatingconditions.

Aniline, which is the most readily available anti-knock material,freezes when cooled to temperatures as low as about 6 C. andconsequently would not give satisfactory operation at temperaturesapproxi- -1nating this point.

In order to overcome this tendency of aniline to freeze, a substance isadded which will lower the freezing point of the aniline or form amixture which has a sufiiciently low freezing point. Such a substanceshould preferably be one which does not interfere with the operationofthe engine or with the function of the aniline as an anti-knockmaterial. A satisfactory material for this purpose is ortho t luidine,which is itself an anti-knock material. Another suitable material forthe purpose is xylidine, which is-also an anti-knock material. Arelatively small proportion of either one or a mixture of these twomaterials will reduce the freezing point of aniline, or the mixture ofaniline with the addition, to temperatures considerably belowthefreezing point of the aniline by itself.

This mixture of materials however becomes too viscous to allow its usein injectors at these low temperatures, and it becomes desirable to adda material which will reduce the viscosity and'which will reduce therate of increase in viscosity on cooling. 1

' A material which is satisfactory for this purpose is unsaturatedgasoline (unsaturated in hydrogen, for example, the olefinic seriesincluding decylene and. monylene) and the preferred unsaturated gasoline.is one having an unsaturation of approximately 88 to 40%. v

In cases where the anti-knock liquid is to be used under conditions inwhich the temperature never reaches a point below about 0 (3., it willbe found that the mix 'ture of aniline and unsaturated gasoline willgive satisfactoryoperation, however if this mixture without the blendingagent is reduced to temperatures as low as 6 or -7 C. the aniline willbegin to separate out. The preferred composition and one that has beenfound to possess the desired physical and chemical characteristicsWithin a temperature range of approximately C. to approximately 30 C.is' composed of aniline, six parts unsaturated gasoline (havinsubstantially 38 to 40% unsaturation) t ree parts; and the blendingagent (consisting of substantially equal parts of ortho toluidine andxylidine) two parts.

Instead of the mixture .of equal parts of ortho toluidine a" ylidine asindicated in the last paragra being used as a blending agent, either oneof thesematerials may be used. I While the specific proportions mentionaniline as the anti-knock material to be used, it should be understoodthat other antiknock materials may be substituted therefor, such asother aromatic amines andthat other blending agents may be substitutedfor the chemical classes are called, herein, aniline addition substancesof the viscosity reducing type. 'lhcrefore, where in the claims theexpression anti-knock mater1als,

blending agent, viscosity reducing material have been used, theseexpressions are intended to cover not only the materials specificallymentioned, but also these and any other materials which may besubstituted therefor, having the same function.

The mixture above described will remain a homogeneous liquid at thelowest temperature -mentionied, its components will not separate oncooling, it will not form a jelly tl'iroughout the temperature rangeordinarily'encountered and its viscosity will not materially increase.The change in temperature from 26 C. to 0 C. of this mixture increasesthe viscosity only sufliciently to increase the time required for agiven amount of it to run through a given size orifice, about 6%. Theviscosity of aniline changes with the same temperature changesufiiciently to increase its time of running through the same sizedorifice about 18%.

The addition of the blending agent is not required unless the materialis to be subjected to temperatures below 0 0., although its presence isnot objectionable but is even advantageous.

The proportion of gasoline in the above mixture may be varied with aconsequent variation in the viscosity change, If less gasoline isuse'din the mixture, the viscosity will increase at a somewhat greaterrate.

to-rial is to be used.

In the above description, the proportions given are parts by volume.

It should be noted that the invention is not limited to the exactproportions given as these may bevaried without departing from thespirit of the invention and the exact proportions will depend to someextent upon the conditions under. which the ina- If the lowesttemperature to which. the operation will be subjected its severaldegrees above (I, it will not be necessary to use the blending agent anda somewhat smaller proportion of the unsaturated gasoline may also beused, although unsaturated gasoline is' not objectionable but is of anadvantage in the mixture, in that, by increasing the bulk and fluidityof the mixture, more exact regulation of the flow of the mixtureandbetter distribution of the anti-knock material may be obtained.

While the specific composition-- herein shown'and described, constitutesa preferred form of embodiment of the invention, it is to be understoodthat other forms might be adopted, all coming within the scope of theclaims which follow.

I claim:

1. A composition aniline, unsaturated ing agent.

2. A composition of matter comprising aniline, six parts; unsaturatedgasoline of about 88 to 40% unsaturation, three parts;

of matter comprising gasoline, and a blendand a blending agent for theaniline and gasoline, two parts.

3. A composition of matter comprising aniline mixed with about half itsvolume of unsaturated gasoline together with a blending agent comprisingortho toluidine.

4. A composition of matter comprising aniline, and unsaturated gasoline.

In testimony whereof Ihereto aflix my signature.

THOMAS MIDGLEY, Jul

